Fan blade iron isolation

ABSTRACT

A ceiling fan is disclosed having an electric motor ( 13 ) with a bottom mounting plate ( 14 ) to which an annular array of blade irons ( 16 ) are coupled, each having a blade ( 17 ) mounted thereto. Each blade iron has a motor mounting flange ( 21 ) with a recess ( 23 ), an end tongue section ( 26 ), and an end groove section ( 27 ) configured to receive the end tongue section. The end groove section includes an alignment pin ( 28 ) and a threaded mounting hole ( 29 ). The end tongue section includes an alignment hole ( 30 ) configured to receive the groove section alignment pin, and a countersunk hole ( 31 ) which is aligned with a mounting hole in the blade iron groove section. A threaded mounting screw ( 32 ) is passed through countersunk hole ( 31 ) and into mounting hole ( 29 ). Each mounting flange is coupled to its two adjacent mounting flanges to provide limited movement therebetween.

TECHNICAL FIELD

This invention relates to a fan system for mounting blade irons andblades, and specifically to systems for isolation of the blades of aceiling fan from vibrations of the drive motor.

BACKGROUND OF THE INVENTION

Many different types of fans exist today, such as ceiling fans, tablefans, pedestal fans, and fans used in conjunction with mechanicalequipment. Most of these fans include a blade and a blade mount or bladeiron which couples the blade to the motor.

Electrically powered ceiling fans typically have a motor mounted withina stationary housing that is suspended from a ceiling. In operation, themotor rotates an annular array of individual extensions in the form ofblade mounts or blade irons. Each blade iron is associated with a blademounted thereto.

The blades of ceiling fans are usually coupled to the blade irons bypassing mounting screws through holes in the blade and into threadedholes in the blade iron. The blade irons are then mounted to the motor.

Ceiling fans are particularly susceptible to the transmission ofmotor-induced noises since by reason of their large area and length, theblades tend to act as resonating or sound transmitting devices, and thustend to impart into the air, as noise, vibrations or the like which theblades receive from the drive motor. The drive motors themselves, whilerelatively quiet by themselves, nevertheless when used to drive ceilingfan blades can impart objectionable noises to the surrounding atmospherethrough the blades. Thus, a noisy stator caused for example by slightlyloose stator laminations, which would produce an otherwise relativelyunobjectionable and unnoticeable stator hum, may at times be transmittedthrough the motor structure through the blade-mounting cage or rotor tothe blades themselves and produce an objectionably loud noise.Similarly, rotor vibrations or noises and bearing noises may beamplified by the blades and become objectionable.

Accordingly, it is seen that a need remains for a ceiling fan systemthat can restrict the transmission of noise to the rotating blades. Itis to the provision of such therefore that the present invention isprimarily directed.

SUMMARY OF THE INVENTION

In a preferred form of the invention a fan comprises an electric motor,an annular array of blade irons, and a ceiling fan blade associated witheach blade iron of the annular array of blade irons. Each blade iron hasat least one mounting hole therein and an elastomeric grommet positionedwithin the mounting hole. Each blade iron of the array of blade irons iscoupled to two oppositely disposed other blade irons of the array ofblade irons.

BRIEF DESCRIPTION OF THE DRAWING

FIG. 1 is a perspective view of a ceiling fan embodying principles ofthe invention in a preferred form.

FIG. 2 is a perspective view of a portion of the ceiling fan of FIG. 1.

DETAILED DESCRIPTION

With reference next to the drawings, there is shown a ceiling fan 10having an electric motor 13 connected to a source of electric power byunshown wires. The motor 13 includes a bottom mounting plate 14 coupledto the rotor so that it rotates during operation of the motor. The motorbottom mounting plate 14 has an annular array of threaded mounting holes19. The ceiling fan 10 also includes an annular array of blade irons 16coupled to the mounting plate 14, each having a blade 17 mounted theretoin conventional fashion.

Each blade iron 16 has a motor mounting flange 21 configured to becoupled with the bottom mounting plate 14 of the electric motor 13. Eachmounting flange 21 has a depression or recess 23 extending from thebottom surface 24 and inward surface 25, an end tongue section 26, andan end groove section 27 configured to receive the end tongue section26. The end groove section 27 includes an alignment pin 28 and athreaded mounting hole 29. The end tongue section 26 includes analignment hole 30 configured to receive the groove section alignment pin28, and a countersunk hole 31 which is aligned with mounting hole 29. Athreaded mounting screw 32 is passed through tongue section countersunkhole 31 and threaded into groove section mounting hole 29. As such, eachmounting flange 21 is coupled to its two oppositely disposed andadjacent mounting flanges 21 with the tongue and groove sectionsproviding limited movement therebetween. The recess 23 extends from thebottom surface 24 less than the full thickness of the mounting flangeand thus leaves a relatively thin section 35 of the flange. The recess23 also includes a semi-circular inwardly opening aperture or slot 38,which interrupts the inward surface 25 at a relatively narrow throat 39.The slot 38 is generally aligned with the threaded mounting hole 19 ofthe bottom mounting plate 14.

An elastomeric isolation means, in the form of a rubber grommet 40, isconfigured to be received substantially within the recess 23 andparticularly supported on the thin sections 35 within the slot 38. Thegrommets 40 have a generally cubic shape and are provided with aninternal clearance opening 42 which extends axially therethrough. Theside walls of the grommet 40 are provided with opposed outwardly openinggrooves 44, which grooves are proportioned to receive the sections 35 ofthe mounting flange, at the slots 38, when the grommet is pressed intoplace and seated in the recess 23. When the grommet is thus seated, aportion of the grommet extends below the section 35 into the recess 23,but the axial thickness of the grommet 40 is such that the portion whichextends into the recess is fully contained within the recess. Anotherportion of the grommet 40 extends above the upper surface of themounting flange when the grommet is inserted. The narrow throat 39 tendsto retain the grommet in place.

The opening 42 in the grommet is adapted to receive drive means in theform of a threaded headed stud 50. The stud 50 is only partiallythreaded at its outer end 52. The threads are intended to be received inone of the mounting holes 19 of the mounting plate 14. The stud 50extends into the mounting plate only to a predetermined depth defined bythe depth of the threads 52, and when the same are inserted through thegrommet openings 42, the mounting flanges 21 are suspended below themounting plate on the enlarged heads 51 of the studs 50. The grommets 40preferably are not drawn into direct contact with the mounting plate 14.

The grommets 40 provides means together with the stud 50 for suspendingthe blade irons 16 from the motor mounting plate 14, thereby eliminatinga metal-to-metal contact. The entire weight of the fan blade 17 andblade irons 16 is carried on the studs 50 through the resilient couplingdefined by the grommets 40. The enlarged head 51 of the stud is receivedadjacent the outer surface of the grommet 40, and thus the weight of theblade irons and blades normally is transmitted to the heads fo the studsthrough the grommets 40. The connected blade irons with the capturedgrommets 40 is free to slide slightly up and down on the threaded studs.The purpose of the slight axial freedom of movement is to provide fullisolation of the blade irons from the mounting plate 14.

It should be understood that the invention provides an elastomericattachment, free of any direct metal-to-metal contact, between the bladeirons 16 and the motor mounting plate 14. Any vibrations in the motorwill tend to be absorbed in the grommets 40, thereby effectivelyisolating the blades 17 from the effects of such direct transmission ofvibration.

It should be understood that the current invention is not intended to belimited to ceiling fans and may apply equally to all types of fans. Itshould also be understood that the current invention is not limited to acertain number of blades or blade irons.

It thus is seen that a ceiling fan is now provided which isolates motornoises and vibrations in a fan. While this invention has been describedin detail with particular references to the preferred embodimentsthereof, it should be understood that many modifications, additions anddeletions, in addition to those expressly recited, may be made theretowithout departure from the spirit and scope of the invention as setforth in the following claims.

1. A fan comprising, an electric motor; an annular array of blade irons,each blade iron having at least one mounting hole therein and anelastomeric grommet positioned within said mounting hole, each bladeiron of said array of blade irons being coupled to two oppositelydisposed other blade irons of said array of blade irons; and a ceilingfan blade associated with each said blade iron of said annular array ofblade irons.
 2. The fan of claim 1 wherein each said blade iron includesa mounting flange having a first end and a second end opposite saidfirst end configured to mate with said first end of another said bladeiron of said array of blade irons, whereby said first end of one bladeiron is coupled to the second end of an adjacent blade iron.
 3. The fanof claim 2 wherein said first end is coupled to said second end ofanother blade iron through a mounting screw.
 4. The fan of claim 3wherein said first end includes an alignment pin and said second endincludes an alignment hole configured to receive said alignment pin ofanother blade iron of said array of blade irons.
 5. A fan comprising, anelectric motor; an annular array of blade irons, each blade iron havingat least one mounting hole therein and an elastomeric grommet positionedwithin said mounting hole, each blade iron of said array of blade ironshaving a mounting flange, each blade iron mounting flange of said arrayof blade iron being coupled to a pair of adjacent mounting flange so asto form a ring; and a ceiling fan blade associated with each said bladeiron of said annular array of blade irons.
 6. The fan of claim 5 whereineach said blade iron mounting flange includes a first end and a secondend opposite said first end configured to mate with said first end ofanother said blade iron of said array of blade irons, whereby said firstend of one blade iron is coupled to the second end of an adjacent bladeiron.
 7. The fan of claim 6 wherein said first end is coupled to saidsecond end of another blade iron through a mounting screw.
 8. The fan ofclaim 7 wherein said first end includes an alignment pin and said secondend includes an alignment hole configured to receive said alignment pinof another blade iron of said array of blade irons.
 9. A fan comprising,an electric motor; a plurality of blade irons, each said blade ironhaving a mounting flange having a first end and a second end, said firstend of one said blade iron being coupled to said second end of anothersaid blade iron of said plurality of blade irons, and a elastomericmember positioned between said mounting flanges of said plurality ofblade irons and said electric motor; and a ceiling fan blade associatedwith each said blade iron of said annular array of blade irons.
 10. Thefan of claim 9 wherein said first end is coupled to said second end ofanother blade iron through a mounting screw.
 11. The fan of claim 10wherein said first end includes an alignment pin and said second endincludes an alignment hole configured to receive said alignment pin ofanother blade iron of said array of blade irons.
 12. The fan of claim 9wherein said mounting flange includes at least one mounting hole thereinand wherein said elastomeric member is an elastomeric grommet positionedwithin said mounting hole